Mixing apparatus, especially adapted for mixing pulverized materials



March 28,1944. E, N A 2,345,053

MIXING APPARATUS, ESPECIALLY ADAPTED FOR MIXING PULVERIZED MATERIALS Filed Oct. 251, 1940 2 Sheets-Sheet 1 Patented Mar. i: 1944 MlXI NG APPARATUS, ESPECIALLY ADAPTED roa-Mixmd PULVERIZED MATERIALS Johannes Ewardus Nauta, Over-veen, Netherlandsfvested in thejilien Property Custodian Application October 31, 1940, Serial No. 363,778

In the Netherlands November 13, 1939 6 Claims. (Cl. 259-40) This invention relates to a mixing apparatus,

which is particularly adapted for mixing pulverized materials, such as flour, and which comprises a stationary mixing trough having an outlet opening for the mixed product at its lower end and being provided with a mixing screw which is driven in such a manner that the contents of the trough are conveyed from the lower end to the upper end thereof and then fall back again in the mixing trough.

In the known mixers of the above mentioned kind the mixing or converging screw is centrally mounted in the mixing trough. This presents the disadvantage that in most cases the product leaving the mixing trough is incompletely mixed. Especially when the product is somewhat moistened or contains a certain percentage of syrup or molasses, it partially adheres to the side walls of the mixing trough, so that the trough cannot be wholly emptied out and the finished product will be of non-homogeneous composition. This is also the case with flour having added thereto some heavy mineral substances. These heavy substances are forced outwardly by the rotating screw and then stick to the side walls of the trough, thus being prevented to be thoroughly mixed in the product.

One of the primary objects of the invention is to obviate the above mentioned drawbacks of the known mixers and to achieve a mixing device which is very simple of construction and,

effective in use and which enables a thorough mixing so as to obtain a finished product of great homogeneity with practically no losses.

A further object of this invention is to obtain the above mentioned results in mixing troughs of conical shape over the whole of their length, as well as in troughs of greater capacity being substantially of cylindrical form and only conical at their lower part. A still further object is to provide for an arrangement which enables to introduce syrup. molasses and other liquid or plas- Fig. 3 shows another embodiment having a trough of the same shape as in Fig. 2.

Referring to Fig. 1 the mixing trough is of conical shape over the whole of its length. On the upper side of the trough i and coaxially with the vertical axis thereof a driving shaft 2'is mounted which is rigidly fixed to a crank arm 3. In the outer extremity of said crank arm 3 the shaft 4 of the helical mixing screw 5 is rot'atably mount ed. The screw 5 takes an inclined position within the trough and is practically parallel to the conical side walls of the trough. By means of a ball and socket joint or a universally Jointed coupling 6 of known construction, which may also be replaced by an appropriate flexible coupling, the lower extremity of the screw shaft 4. is connected to a centrally disposed driving shaft 1 which passes through the bottom of the mixing trough. v

When the shaft 7 is driven, the screw shaft rotates about its own axis. When the shaft 2 is driven at the same time (this is done, however, with a number of revolutions which is smaller than that of the shaft 1), the screw shaft i also revolves about the .central axis 8 of the mixing trough, causing the screw 5 to move slowly along the side walls I. Due to the fact that the mixing screw 5 is situated near the side walls of the trough and moves along these walls, a thorough mixing of the contents of the trough will be assured and it will be no longer possible that portions of the contents stick to the walls. Apart from a better mixing effect, the mixing operation is also effected morerapidly than in ordinary mixers of this kind, so that the output of the apparatus will be considerably increased.

The revolution of the mixing screw about the -axis 8 may be obtained in any other convenient 4 is driven about its own axis by means of the.

driving shaft 1, the pinion at the upper end ofthe shaft 4 will move along the rack or stationary toothed wheel, thus causing a slow revolving movement of the screw 5 about the central axis The mixing trough is provided at its lower end with an outlet II) which may be shut by means of a slide 9 or the like. The shaft 1 may be provided in a known manner with a stirring blade I I.

The materials to be mixed areofpulverized or powdery nature. When a certain percentage of syrup, bil, water, molasses or other moist ingredients is added, the mass in the trough becomes somewhat crumbling, but it does not take a.-

openings arranged in such a manner that, when the mixer is in operation, the openings lie behind in the direction of revolution of the screw, so as to prevent their obstruction by the materials to be mixed. The hollow shafts may be supplied under pressure with syrup, molasses, oil or other liquid ingredients, so that it i possible to add' such ingredients to the dry materials during the above described embodiment. the mixing screw consists oftwo parts, of which the upper part I is parallel to the cylindrical wall i2, whereas the lower part li lies parallel to the conical wall ll- Centrally disposed in the mixing trough is a vertical driving shaft ii which is rotatably mounted with its lower end in a step bearing ll. Rigidly connected to this shaft I6 is a crank arm I! having at its outer extremity a bearing I! in which the shaft 20 of the upper screw part H is rotatably mounted. The said shaft 20 is connectedby means of a ball and socket Joint 2| or a such like Jointed or flexible coupling to a bush 22 carrying the lower screw part l5. By means of ball bearings the bush 22 is rotatably mounted on a shaft 23 rigidly connected to the lower end of' the driving shaft IS. The driving shaft ll carries at its upper extremity a bevel gear 24 which is driven with a relatively small number of revolutions. When driving the shaft I a revolving movement is imparted to the screw parts I and [5 along the side walls l2 and I of the trough.

In order to rotate the screws 14 and i5 about their own axes, the shaft 20 is provided at its upper end with a sprocket, wheel 25 connected by means of a chain 26 to a sprocket wheel 21 mounted on the lower part of a bush 28 surrounding the shaft l6 and carrying at its other end a bevel gear 29 which is driven with a greater number of revolutions than the gear 24.

either on the upper or on the lower side of the mixing trough. In the latter case the supply may, e. g., be effected by means of a centrally disposed conveying screw joining the lower end of the screwpart l5.

In the modification according to Fig. 3 the central driving shaft 5 is made of short length and it only reaches to the crank arm it which again carries in the hearing I! the upper screw mixing operation. Since the nozzles revolve with the screw or screws-along the side walls of the mixing trough. the ingredients will be uniformly distributed over the contents of the trough.

In known mixers the ingredients, as well as the pulverized products are brought together in a continuous stream before reaching the mixing trough. If by any reason the proportion of ingredients and pulverized materials is not correctly adjusted, the finished product will be necessarily of incorrect composition. According to the invention, however, the pulverized materials and the ingredients may be brought together in the mixing trough and it does not matter when the velocity of the supplying stream of the pulverized materials and that of the stream of ingredienfls are not correctly and precisely adjusted to each other. Due to the uniform distribution of the ingredients through the contents of the mixer, it is only necessary to supply a definite quantity of such ingredients t each filling of for thoroughly mixing the contents of the trough will be considerably reduced.

What I claim is:

1. In an apparatus for mixing and discharging pulverized and substantially dry materials, such as flour, a stationary mixmg receptacle formed with an outlet at the lower end, a shaft extending longitudinally of the receptacle, the lower end of the shaft being supported for rotation in the axial line of the receptacle, the upper end of the shaft being supported for rotation at a point wholly outside the axial line of the receptacle, a

helicoid conveyor blade fixed on the shaft and shaft 20. This screw shaft 20 is now connected by means of the coupling 2| to a lower screw shaft 32 carrying the screw part l5. By means of a second ball and socket joint? or similar coupling 33 the shaft 32 is connected to acentral driving shaft 34 at the lower end of the mixing arranged to convey the pulverized material upmadly in the receptacle in the rotation of the shaft, driving means to rotate the shaft on its own axis, and an independent means to revolve the shaft on the axis of the receptacle.

2. A construction as defined in claim 1 wherein the shaft is rotated on its own axis at a speed in includes a driving element disposed in the axial line of the receptacle and having swivel connection with the lower end of the shaft, and wherein the driving means at the upper end of the shaft trough. This shaft 3| causes the rotation of nozzles, pipes or the like communicating with the interior of the shaft or shaft The nozzles,

which may be fixed upon or below the blades of the mixing screw or screws. have their outlet includes a driving element arranged in the axial line of the receptacle, an arm carried by the driving element within the receptacle, and means for rotatably supporting the upper end of the shaft at the free end of the arm.

4. In an apparatus for mixing and discharging pulverized and substantially dry materials, such as flour, a stationary mixing receptacle formed with a discharge outlet at the lower end, a shaft the t being supported ior rotation in the axial lower end being without the axial line of the receptacle, a helicoid conveyor blade extendlne throuzhout the shaft and arranged to conveythe pulverized material upwardly in the receptacle in the rotation of the shaft, means to rotate the shaft on its own axis, and independent means to 10 revolve the shaft on the axis of the receptacle.

5. An apparatus as defined in claim 4, wherein the receptacle is oi, truncated cone form having its laraeat diameter at the upper end. the shaft e of the receptacle, the shaft beyond such walla oi the cone.

8. An apparatus as deiined in claim 4. wherein the receptacle in the lower part ie of truncated cone iorm having its largest diameter at the upper end and in the upp r part oi cylindrical i'orm having the same, diameter as the upper end of the truncated cone.. the shalt carryina the conveyor blade consisting of two parts having swivel connection with each other and or which the upper part is parallel to the walls of the cylinder and the lower part is parallel to the walla oi the cone.

JOHANNES EWARDUB NAUTA.

CERTIFICATE or CORRECTION. Patent No. 2,51 .5,065. March 2 191m.

- JOHANNES maws NAUTA.

It iehereby certified-that errqiappears in the printed'epeoification or the above numbered patent requiring correction as follows: Page 1, first column, line 12, for "converging" read conveying-q end that the said Lettere Patent should be read with this correction therein that the" same in? cqnform to the record-0'1 the case in the Patent Office.

Signed and sealed this 25rd day of May, A. D. 19141;.

I Leslie Frazer (Seal) Acting Commieeioner of Patents. 

